LSAT Explanation PT 42, S4, Q7: Two different dates have been offered

LSAT Question Stem

The statements above, if true, most strongly support which one of the following conclusions about the last ice age and its aftermath in North America? 

Logical Reasoning Question Type

This is a Most Strongly supported question. 

Correct Answer

The correct answer to this question is E. 

LSAT Question Complete Explanation

Let's first analyze the passage. It presents two different dates for the approximate end of the last ice age in North America. The first date is based on when warmth-adapted open-ground beetles replaced cold-adapted arctic beetles, and the second date is based on when ice masses yielded to spruce forests. The first date is more than 500 years earlier than the second.

Now, let's identify the question type. This is a Most Strongly Supported (MSS) question, which asks us to find the conclusion that is most strongly supported by the information in the passage.

Let's examine each answer choice:

a) This answer choice suggests that warmth-adapted beetles ceased to inhabit areas with spruce forests. However, the passage does not provide any information about the relationship between beetles and spruce forests. We cannot conclude this from the passage.

b) This answer choice claims that sediments with cold-adapted beetle fragments can also be expected to contain spruce-pollen grains. However, the passage states that the first date (based on beetles) is more than 500 years earlier than the second date (based on spruce forests). This means that the presence of cold-adapted beetles does not guarantee the presence of spruce-pollen grains. We cannot conclude this from the passage.

c) This answer choice states that ice masses continued to advance through North America after the end of the ice age. The passage does not provide any information about the movement of ice masses after the end of the ice age. We cannot conclude this from the passage.

d) This answer choice claims that the species of cold-adapted arctic beetles that inhabited areas covered by ice masses died out towards the end of the last ice age. While the passage states that warmth-adapted beetles replaced cold-adapted beetles, it does not provide any information about the extinction of the cold-adapted beetles. They could have migrated to other areas or adapted to the changing environment. We cannot conclude this from the passage.

e) This answer choice states that warmth-adapted beetles colonized new terrain faster than soil changes and seed dispersion established new spruce forests. This conclusion is supported by the passage, as it tells us that the first date (based on beetles) is more than 500 years earlier than the second date (based on spruce forests). This indicates that the beetles colonized new areas before the spruce forests were established.

Therefore, the correct answer is E.